feat: show suffix-matched metric coverage in host info threshold table

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

hbd/server/http.py

@@ -143,6 +143,25 @@ def _build_host_info(host, threshold_checker=None) -> dict:
     thresholds = None
     if threshold_checker is not None:
         raw = threshold_checker.get_thresholds_for_host(host.name)
+
+        # Build reverse coverage: which metric paths suffix-match to each threshold.
+        # Mirrors the logic in ThresholdChecker._find_threshold.
+        coverage: dict = {}
+        for plugin_name, samples in host.plugin_data.items():
+            if not samples:
+                continue
+            _, pdata = samples[-1]
+            for field_name in pdata:
+                full_path = f"{plugin_name}.{field_name}"
+                if full_path in raw:
+                    continue  # exact match — the threshold IS this metric
+                parts = field_name.split("_")
+                for i in range(1, len(parts)):
+                    candidate = f"{plugin_name}." + "_".join(parts[i:])
+                    if candidate in raw:
+                        coverage.setdefault(candidate, []).append(full_path)
+                        break
+
         thresholds = sorted(
             [
                 {
@@ -150,6 +169,7 @@ def _build_host_info(host, threshold_checker=None) -> dict:
                     "warning": tc.warning,
                     "critical": tc.critical,
                     "operator": tc.operator.value,
+                    "covers": sorted(coverage.get(tc.metric_path, [])),
                 }
                 for tc in raw.values()
             ],